The advent of integrated lighting installations, consisting of an ever growing number of individually controllable light sources, luminaires, lighting arrangements and the like with advanced rendering capabilities, may be regarded as transforming lighting systems for both professional and consumer markets. This brings a need for an intuitive control capable of fully exploiting the rendering capabilities of the complete lighting infrastructure. Several approaches have been proposed to control light sources, luminaires, lighting arrangements and the like.
A first example involves wall-mounted control. At commissioning time a set of wall-mounted controls are installed, each of them controlling an individual or group of light sources or luminaires, possibly with optimized controls for each type of control within the set.
A second example involves having a separate remote control unit for each individual light source or luminaire. This may be regarded, by means of the remote control unit, as a more or less straight forward extension of the above disclosed wall switch control.
A third example involves iterative selection of the individual light sources or luminaires. A user is provided with a simple remote control unit capable of controlling all light sources or luminaires which the remote control unit has been commissioned with. The remote control unit is able to control a single luminaire at a time, but it may also allow a user to browse through all the luminaires, for example by manipulation of a user interface provided on the remote control unit (e.g. by using “previous” or “next” buttons). A digital version of such a concept has also been developed, which adopts a touch screen device as a remote control unit, so that, once a light source or luminaire is selected, a light control optimized for such a light source or luminaire is displayed to the user (e.g. color temperature for a light source or luminaire with tunable white; or a color wheel for an RGB light) by means of the touch screen on the remote control unit.
A fourth example involves the concept of point and control; this approach exploits the principle of coded light and a remote control unit capable of detecting the code of the light source or luminaire toward which the remote control unit is pointed and thereby to identify the light source or luminaire emitting the coded light. Such a remote control unit typically comprises one or more photodiodes for detecting the coded light emitted by the light source or luminaire. In general, coded light has been proposed to enable advanced control of light sources. Coded light is based on embedding of data, inter alia invisible identifiers, in the light output of the light sources. Coded light may thus be defined as the embedding of data and identifiers in the light output of a visible light source, f.i. applying CDMA modulation techniques, wherein the embedded data and/or identifier preferably do not influence the primary lighting function of the light source. Hence, any modulation of the emitted light pertaining to data and/or identifier should be invisible to humans. This allows for applications such as interactive scene setting, commissioning and re-commissioning of networked lighting systems. Coded light may be used in communications applications wherein one or more light sources in a coded lighting system are configured to emit coded light and thereby communicate information to a receiver.
The point and control approach shows the advantage of using coded light as a means to be able to select a luminaire by simply pointing towards it. As noted above, this approach employs a photodiode in order to detect the Coded Light message of each luminaire. It has been proposed to detect and decode coded light by means of a standard camera.
International application WO 2009/010926 relates to a method for processing light in a structure where the light sources emit light carrying individual codes. A camera is arranged in a camera position of the structure and registers images of spots of the light. WO 2009/010926 is based on an insight that by using a camera for registering images of the light emitted from the light sources after installation thereof, and recognizing the individual codes in the registered images, it is possible to obtain a fast and at least substantially automatic determination of light source properties. The camera may comprise an image detector comprising a matrix of detector elements each generating one pixel of the registered image. The camera registers images of illuminated areas at a frequency that corresponds to, or is adapted to, the modulation frequency of CDMA modulation. Thereby it is possible for the camera to generate images that capture different CDMA codes of the different illuminated areas.